Furnace



Au 7, 192a. 1,679,364

7 E. LUNDGREN FURNACE Filed on. 16, 1925 2 Sheets-Sheet l .Patented Aug. 7, 19 28.

' UNITED STATES PATENT OFFICE.

EDWIN LUNDGREN, OF FREDERICK, MARYLAND, ASSIGNOR TO COMBUSTION ENGL- NEERING CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

FURNACE.

Application filed October 16, 1923. Serial No. 668,799.

An object of the invention is to provide a novel and improved furnace of the underfeed stoker type.

Another object of the invention is to provide a novel and improved dumping grate structure.

Another object of the invention is to provide a dumping grate structure having novel and improved means for supplying a cooling agent to the parts of the structure that are exposed to the heat of the furnace,

Another object of the invention is to provide a dumping grate structure having novel and improved means for supplying air to the fuel supported thereby.

With these and other objects in view, the features of the invention consist in certain constructions, arrangements, and combinations of parts hereinafter described and claimed, the advantages of which will be obvious to those skilled in the art.

The several features of the invention will be clearly understood from the following description and accompanying drawings, in which,--

Figure 1 is a longitudinal sectional view, partly in elevation, of the rear portion of an underfeed stoker embodying the features of the invention in their preferred form;

Fig. 2 is a sectional plan view, on an enlarged scale, of a portion of the dumping grate structure illustrated in Fig. 1;

Fig. 3 is a sectional elevation taken on the line 33 of Fig. 2; A

Fig. 4 is a sectional view, partly in elevation, taken on the line 44 of Fig. 3;

, Figs. 5 and 6 are sectional views taken on the line 55 and 6-6 respectively of Fig. 2; 'Fig. 7 is a sectional view, partly, in elevatidn, taken on the line 77 of Fig.3;

Fig. 8 is a view in perspective of atomponent part of the grate structure; and

Fig. 9 is a sectional view taken substantially on the line 99 of Fig. 2.

The underfeed stoker illustrated in the drawings is provided with the usual arrangement of retorts 2, tuyere structures 4. and wind box 6; and is further provided with a bridge wall 8 spaced a distance to the rear of the retorts, and an ash pocket 10 between the rear ends of the retorts and the bridge wall.

In the illustrated construction two I- beams 12 and 14 are provided that extend the width of the furnace and support the rear end of the fuel retorts and tuyere structures. These I-beams 12 and 14 constitute the front and rear walls, respectively, of an air passage or chamber 16 which is in communication with a suitable source of forced air supply through a conduit 18 leading through the bottom wall of the air chamber. The stoker is further provided with two I- beams 19 and 20 that extend the width of the furnace and support the bridge wall 8. These I-beams 19 and 20 constitute the front and rear walls, respectively, of an air passage or chamber 22 corresponding to the air chamber 16 the air chamber 22 being in communication with a suitable source of forced air supply through a conduit 24 -leading through the bottom of the chamber.

As shown the stoker is further provided with a pair of oppositely disposed dump grates 26 and 28 which are mounted on parallel rock shafts 27 and 29,respectively. Each dump grate is madein a plurality of sections of hollow construction to which air is supplied from the air chambers 16 and 22 through hollow brackets 30 and 32, respectively, in which the rock shafts 27 and 29 are mounted, as hereinafter described. As the two dump grates 26 and 28 and their rock shafts 27 and 29 and supporting brackets 30 and 32 are similarly constructed, a description of one will suflice for both, the dump grate 26 and its shaft 27 and brackets 30 being shown in detail in the drawings and specifically described herein.

Each bracket 30 is provided with a cylindrical end portion 34 of hollow open cylinder construction, and an arm 36 of hollow construction that registers with an inlet opening 38 in the I-beam 14. The cylindrical portion 34 of each bracket is provided with a longitudinally extending and upwardly and rea-rwardly inclined U-shaped wall 40 forming an upwardly opening bearing slot 42 for the reception of a rounded portion of the rock shaft 27. The bearing slot 42 in each bracket is closed by a cap 46 that enters the slot and engages the upper surface of the shaft so as to complete the cylindrical shape of the bearing.

As shown the dump grate 26 is made in a plurality of sections arranged side by side in close proximity. The several grate sections are mounted on squared portions 48, respectively, of the rock shaft 27, each section being arranged between two of the brackets 30. The grate sections are each provided with a tubular portion or sleeve 50 having open ends, each of which surrounds the adjacent end of the cylindrical portion 2-31 of the adjacent bracket 30. Each sleeve 50 is provided with a partition 52 intermediate of its ends that embraces a squared portion of the rock shaft. Each sleeve 50 iS split longitudinally so as to form upper and lower sections 5i and 56 so as to permit it to be easily applied to the rock shaft and supporting brackets, the part of the partition associated with the upper section 54 having a horizontal surface 58 that engages the top side of the squared portion of the rock shaft, and a vertical surface 60 that engages the rear vertical side of the rock shaft; and the part of the partition 52 associated with the lower sleeve sections 56 having a vertical surface 62 that engages the rear side of the squared portion of the rock shaft, and a horizontal surface 64 that engages the lower horizontal surface of the rock shaft. The two sleeve sections 54 and 56 are secured together about the rock shaft and about the cylindrical portion of the supporting brackets by suitably arranged clamping bolts 66 and 67, the bolts 66 extending through apertures in the two parts of the partition 52, and the bolts 67 extending through a forwardly projecting flange 68 on the lower section 56 and through a corresponding flange 70 on the upper section 54. Each grate section is further firmly held on the rock shaft by means of a set screw 72 which is screw-threaded through an aperture in the upper part of the partition 52 and engages the rock shaft.

The upper section 54 of each sleeve extends over substantially one-half of the cylindrical portion of its supporting brackets 30 and extends the entire width of the dump grate section. The lower section 56 of each sleeve is made of suitable length so as to surround the lower portion of the projecting ends or hubs of its supporting brackets, with its extreme ends spaced from the webs 36 of the brackets so as to permit the dump grate to be freely rocked about the cylindrical portions of the brackets. The ends or hubs of the brackets 30 thus extend into the ends of the sleeves 50; and their extreme ends are arranged adjacent shoulders 71 and 76 on the upper and lower sections of the sleeves, respectively. lVith this construction it will be apparent that air passing through the brackets 30 from the air chamber 16 will be discharged into the ends of the sleeves 50 and at opposite sides of the partitions 52.

Each grate section is further provided with a forwardly projecting body portion 76 which is cast integral with the upper sleeve section This body portion is provided with a plurality of longitudinally extending channels 78 that are U-shaped in cross-section, and are in communication with the interior of the sleeve 50 through their rear ends 80. The vertical walls 82 of adjacent channels 78 are spaced apart and are connected by a transverse web or partition 84 adjacent their rear ends, a partition 86 intermediate their ends, and a partition 88 spaced a distance from their rear ends; and the upper edges of these vertical walls 82 are connected by horizontal wall portions 90. These wall portions 90 are each provided with slots 92 extending between the partitions 8 1 and 86, and slots 93 extending from the partition 86 to the rear end of the channels. The top of the body portion 76 is covered by a cover plate 94, the rear end of which is arranged adjacent a shoulder 96 on the upper section of the sleeve 50, and the forward end of which is curved downwardly and fits over a flange 98 formed on the body portion 76. The cover plate 94 is sccured in position by means of depending lugs 100 thereon that hook underneath a depressed rearwardly projecting flange 102 on the upper section of the sleeve, and by means of bolts 104 that extend through apertures in the cover plate and in the bottom walls of two of the channels 78, the heads of the bolts being countersunk in the cover plate. The cover plate is provided with slots 108 that register with the slots 92 and 93, and with slots 110 above the channels 78 and the spaces in the body portion of the grate section adjacent to the rear ends of the channels.

From the foregoing it will. be apparent that upon air being admitted to the air chamher 16 it will pass through the several brackets 30 and out through the ends of the cylindrical portions of the brackets into the ends of the sleeves 50 of the several grate sections, then through the outlet slots 110 in the top plate to the fuel supported on the dump grate section; and at the same time air under natural draft is permitted to pass upwardly from the ash pit through the slots 108.

As above stated, the dump grate 28 is similar both in construction and operation to the dump grate 26 above described, and thus a dumping grate structure is provided comprising the dump grates 26 and 28 in which there is provision for supplying air under both forced and natural drafts to the fuel supported thereby. One advantage of such a construction is that during the dumping operation and before the accumulation of a large body of fuel and ashes on the fuel supporting surface of the dump gate, the forced draft may be shut off, and when a large body of fuel and ashes has accumulated it may be turned on, the provision for the natural draft permitting a sufficient quantity of air to be supplied to assist combustion of any unconsumed fuel in the body of ashes prior to the turning on of the forceddraft, and to prevent overheating of the parts of the dumping grate structure at this time.

As will be evident to those skilled in the art, my invention permits of various modifications without departing from the spirit thereof or the scope of the appended claims.

What I claim is 1. A furnace having, in combination, two brackets of hollow construction provided with bearings arranged in alinement, a rock shaft extending through said bearings in said brackets, and a dump grate of hollow construction mounted on said shaft between said brackets, said brackets and dump grate having registering openings in the adjacent Sides thereof leading from the interior of said brackets and into the interior of said dump grate.

2.'A furnace having, in combination, a dump grate made in a plurality of sections of hollow construction and arranged side by side to provide a substantially continuous fuel supporting surface extending substantially the width of said grate, each section having a tubular portion with the several tubular portions arranged end to end, a rock-shaft extending axially through said tubular portion and upon which the several sections are mounted, and means for supporting the rock-shaft and for supplying air to the interior of each section through the ends of the tubular portion thereof.

3. A furnace having, in combination, a

dump grate having a tubular portion, and a fuel supporting portion of hollow construction in communication therewith, a rock shaft extending axially through said tubular portion upon which the dump grate is mounted, brackets of hollow construction arranged adjacent the ends, respectively, of 'said tubular portion in which said shaft is mounted, said brackets being in communication with the ends of said tubular portion, respectively, and means for supplying air to the interior of said brackets.

4. A furnace having, in combination, two brackets of hollow construction having hubs projecting toward each other and arranged in axial alinement, a rock shaft, said brackets having bearings in which said rock shaft is mounted, a portion of the rock shaft extending between said brackets being square in cross section, a dump grate mounted on said shaft between said brackets having a tubular portion surrounding the squared portion of said rock shaft and being split longitudinally into a plurality of sections so as to permit said dump grate to be applied to and removed from said shaft upon separating said sections, means for detachably securing said sections together, said dump grate having a fuel supporting portion integral with one of said sections of said tubular portion and in communication with the interior of said tubular portion, said hubs of said brackets projecting ,into the outer ends of said tubular portlon, respectively, and having outlet openings leading into the interior of said tubular portion, and means for supplying air to the interior of said brackets.

5. A furnace having, in combination, a bracket having a cylindrical hollow end portion and a hollow web in communication therewith, a rock-shaft mounted in and'extending through said end portion of said bracket, a dump grate made in a plurality of sections each having a tubular portion, mounted on said rock-shaft at opposite sides of said bracket, the upper portions of the adjacent ends of said tubular portions extending a distance over the upper portion of said cylindrical end portion of said bracket, the ends of said cylindrical portion of said bracket having outlet openings leading into the interior of said tubular portions, and means for supplying air to the interior of said bracket.

6. A furnace having, in combination, a dump grate made up of a plurality of sections of hollow construction arranged side by side to provide a substantially continuous fuel supporting surface extending substantially the width of said grate, a bracket of hollow construction interposed between said sections and having openings in opposite sides thereof for directing air into the interior of said sections, the air entering said sections through openings in the sides thereof adjacent said bracket, a rock-shaft mounted on said bracket and on which said sections are mounted, and means for supplying air tothe interior of said bracket.

7. VA furnace having, in combination, fuel supporting means, an ash pit for receiving the refuse of the fuel therefrom, a dump grate extending across the ash pit and made up of a plurality of sections arranged side by side to provide a substantially continuous refuse supporting portion extending substantially the width of the dump grate, each section having a tubular portion and a hollow web portion projecting therefrom and in communication therewith, a bracket of hollow construction mounted on one of the walls of said ash pit and extending between the ends of the tubular portions of adjacent sections and in communication with the inte riors of said tubular portions, a shaft extending through said tubular portions and through and pivotally mounted in said braeket for supporting said sections and permitting pivotal movement thereof, and means for supplying air to the interior of said bracket.

8. A furnace having, in combination, fuel supporting means, an ash pit for receiving the refuse of the fuel therefrom, and a dump grate of hollow construction extending across the ash pit having openings in its refuse supporting surface for directing air from the interior thereof to the material supported thereby and having air passages extending therethrough to permit air to pass from the ash pit below the dump grate to the material supported thereby independently of the air supplied to the interior of the dump grate, and controllable means for supplying air to the interior of the dump grate.

9. A furnace having, in combination, a bracket having a hollow web portion and a substantially cylindrical end portion having its ends projecting beyond the sides of said web portion, a rock shaft mounted in and extending through said cylindrical end portion of said bracket, a dump grate of hollow construction made in a plurality of sections mounted on said rock shaft at opposite sides of said bracket and each having a portion surrounding the adjacent projecting end of said cylindrical end portion of the bracket, the top surfaces of said sections extending over substantially the entire upper part of said cylindrical end portion of the bracket, and the ends of said cylindrical end portion of said bracket having outlet openings leading into the interior of said grate sections, respectively, and means for supplying air to the interior of said bracket.

10. A furnace having, in combination, a bracket having a hollow end portion, a rock shaft mounted in and extending through said end portion of said bracket, a dump grate made in a plurality of sections of hollow construction mounted on said rock shaft 1 at opposite sides of said bracket and having their top surfaces extending over substantially the entire area of said hollow end portion of said bracket, said hollow end of said bracket having openings leading into the interior of said grate sections, and means for supplying air to the interior of said hollow end portion of the bracket.

EDWIN LUNDGREN. 

